Hydrodesulfurization of oxo alcohols



Oct. 16, 1956 R.' B. MASON ETAL 2,757,222

HYDRODESULFURIZATION OF' OXO ALCOHOLS Filed Jan. 22, 1953 JOI mw we@ @Zini w vm wm Il vv Nv wm mOLLOm @All @nl I1 Baines-on Overmars End.;

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Gbbofvrle nted States Patent O HYDRODESULFURIZATIN F 0X0 ALCOHOLS Ralph B. Mason and Fred J. Buchmann, Baton Rouge,

La., assignors to Esso Research and Engineering Company, a corporation of Delaware Application January 22, 1953, Serial No. 332,738

7 Claims. (Cl. 260-643) 'The present invention relates to a process for purifying toxygenated organic compounds prepared by the carbonyl- .ation of olenic compounds in the presence of a car- Ibonylation catalyst which are subsequently hydrogenated .to form alcohols. More specifically, the present invention relates to an improved method for purification of primary :alcohols by treatment with hydrogen in the presence of .a sulfurand carbon monoxide-sensitive catalyst, such ;as nickel. Still more specifically, the present invention relates to a hydrodesulfurization reaction carried out in :the presence of carbon monoxide-containing hydrogen gas streams Primary alcohols prepared by the Oxo process are Of g great economic importance and of commercial interest lbecause of their use as intermediates in the manufacture :of plasticizers of the diester type by esterication with idibasic acids. Previously, these alcohols have been sup- ',plied mainly by such comparatively costly procedures :as aldol condensation of butyraldehydes, followed by tdehydration and hydrogenation of the resulting unsatur- 'ated octyl aldehyde. The synthesis of oxygenated organic compounds from olenic compounds and mixtures of carbon monoxide and hydrogen under suitable conditions is well known in the art. The olefmic starting material is allowed to react in the liquid state with carbon monoxide and hydrogen in the presence of a metal catalyst, usually an iron group metal catalyst, such as a suitable cobalt compound to form, in a lirst or oxonation stage, organic carbonyl compounds such as aldehydes having one carbon atom more per molecule than the olenic feed material together with some condensed higher molecular weight products such as ethers, acetals, hemiacetals, and esters. The carbonyl compounds which predominate in the product are then subjected to a single hydrogenation to produce the corresponding alcohols, usually in a rather impure state.

Practically all types of organic compounds having an olefinic double bond may be used as starting materials to the tirst or oxonation stage, including aliphatic olens and diolefms, cyclo-olefins, aromatics with olefnic side chains, oxygenated compounds having olenic double bonds, etc. The metal catalyst is preferably used in the form of a fatty acid salt soluble in the oleinic feed stock, such as the naphthenates, stearates, oleates, etc. of cobalt. Suitable general reaction conditions include temperatures of about l50-450 F., pressures of about 100 to 300 atm., HzzCO ratios of about 0.5-4.0:1, liquid feed rates of about 0.2- v./v./hr. and gas feed rates of about 1,000-45,000 standard cu. ft. of H2-l-CO per barrel of liquid olenic feed.

The primary hydrogenation stage may be operated at conventional hydrogenation conditions which include temperatures, pressure, gas and liquid feed rates approximately within the ranges specied above for the first stage. Various known types of hydrogenation catalysts, including nickel, tungsten, molybdenum, but preferably in the form of their oxides and suldes, and others may be "ice used. The liquid product from the primary hydrogenation stage is worked up by distillation to separate the desired alcohols from unconverted olefinic feed material, unhydrogenated carbonyl compounds, and hydrocarbons formed in the process. The sulfactive sulfide' catalysts have been found to be especially useful for carrying out this hydrogenation.

The over-all carbonylation or so-called Oxo reac= tion as outlined above provides a particularly effective method for preparing valuable primary alcohols, particularly of the C4 to C20 range, which find large markets as intermediates for detergents and plasticizers. The Cs and C9 Oxo alcohol products are especially preferred for use in forming esters to be used as plasticizers in lightcolored or colorless plastics and resins. Y

Serious diiculties have been encountered in the primary hydrogenation stage as a result of sulfur poisoning of certain hydrogenation catalysts, when the catalysts used are those such as elementary nickel and others which are sulfur-sensitive. The most readily available oleiinic feed stocks for the oxonation reaction are selected hydrocarbon streams derived from petroleum refinery sources and these frequently have sulfur contents as high as 0.1% or even higher. Furthermore, there are a variety of other ways in which sulfur may be introduced into the alcohol product during both the oxonation and hydrogenation stages for reducing the carbonyl compounds. For instance, the fatty acids used to form the metal oxonation catalyst for the purpose of introducing the metal into the reactor as the metallic naphthenate, stearate, or oleate, will usually be found to contain small amounts of sulfur-containing compounds as contaminants, particularly when the fatty acids themselves are of petroleum origin as they frequently are. The synthesis gas used in the oxonation zone which is primarily a mixture of carbon monoxide and hydrogen also may contain sulfur impurities and, in fact, the gaseous reactants employed in both stages of the Oxo reaction usually contain at least traces of sulfur impurities.

Sulfur which is present in the crude reaction mixture containing the carbonyl compounds tends to be carried through the oxonation stage into the hydrogenation stage where it combines with the hydrogenation catalyst to diminish and even completely destroy catalyst activity unless sulfur-insensitive catalysts are used. The sulfursensitive hydrogenation catalysts are generally of the elementary metallic type and the deactivating eiect of the sulfur on their activity requires frequent reactivation, catalyst replacement, and increased amounts of a catalyst whose cost is definitely a commercial factor and may be prohibitively high. Thus, it has been considered necessary for optimum operation in the hydrogenation step to employ a sulfur-insensitive catalyst. These sulfurinsensitive catalysts include particularly certain metallic sulde hydrogenating catalysts, examples of such catalysts being nickel sulfide, molybdenum sulfide, tungsten sulfide, and mixtures thereof. While these catalysts have the decided advantage of avoiding the inactivation due to sulfur content of the feed stock, they also possess the disadvantage of permitting much of the sulfur to pass unchanged through the hydrogenation zone and, indeed, iu many instances, tend to introduce additional sulfur contamination into the alcohol. Thus, the final crude alcohol products may have a total sulfur content of from 30-100 parts per million and higher.

One of the largest and most important uses developed for the synthetic alcohol products is that of producing esters suitable for plasticizers, by reaction with aliphatic, alicyclic, and aromatic acids or anhydrides, including such examples as phthalic acid, maleic acid, adipic acid, and also phthalic and maleic acid anhydrides, Certain of the synthetic alcohols prepared by the oxonation and hydrof use in clear plastics.

l gienation reaction are known to be especlally suitable for the manufacture of ester plasticizers and particularly for These linclude alcohols from C4 to monoxide sensitive, which is highly undesirable.

C20 range such as the butyl alcohols, the octanols, and the nona'nols. Y

'These estersa're prepared `in standard type esterication eqiiipment'employing reactors made of stainless steel or 'other'inetalfon in 'some' cases, in glass-lined reaction fvessel's. In some instances, particularly when the esters Were-produced 'in "re'actorshaving metallic Vsurfaces eX- posed to the reacting mixtures, the products were found to be deficient as'to'the standards required for plasticizers, in such characteristics as odor, color, and'plasticizing qualities'suchas 'the 'poor weathering tendency ofA the resiiisfandlplastics inivvhichfsuch`plasfici2ers are used. These undesirable "characteristics a`re` believed to be priinarilyfcan` "-byimp'uritiespresent inthe alcohol productand ceft'aiifofthese arecaused particularly by the Y sulfur products Ypresent inl the'al'cohol, although other """ls`vvhic'h'can affect esterlcolor'and odor include pcjlyinerized Aandcloiti'densed higher molecular Weight imities as vvell A'as "unreduced Vcarbonylcompounds and 6th -non-alcoliolic(compounds. "Ithas further been discovered 4that sulfur componnds, especially those of the'aeidietype, are allowedto'remain in impure alcohol 4o1" "a dehyde, [they4 act as catalysts for causing increased condensation reactions vvhioh4 produce acetals and other iii'gir'mbleclar weight" instanties" ofthe undesirable type. In fact, ithasbeen" found'that, in'order to obtain a high v4grade-alcohol vvhi'chadequatelyiineetsiall specifications,

the active, "''olorproducing" sulfur contentshould best be 5reduc to )value somewhere nearve parts per million, valthoughsomewhat higher vtotal sulfur concentrations can be tolerated, the exact limit'of Vtolerance depending upon "Infgeneral, the Ysulfur inlthe synt'heticOXo alcoholsis "inthefforni of'or'gahic'ally 'cmbinedsulfun Although all typesfofbrgnic Vimpurities in which the sulfur occurs .have not beenfullyv determined, it is believed that'Y the sulfur is'pre'sentin a variety of forms and that it is generally deleteriousinmrriost forms When occurring in the final alcohol.' Sulfur-containing contaminants cause both odor and color problems as Well as'act as accelerators to give uhuiantedpiopei'ties to the alcohols. The iinished'alcohol 'should Ncontain a'minimum of sulfur-containing cornpounds. l v 'An .'eircllentimeans of purifying and removing lsulfur fromthe 'distilledalcohol productV prepared in the mannerdesciibed has/been' the treatment of the alcohol product v'iithadditinalhydrogen in the presence of an active catalyst', suchas nickel, at relatively moderate conditions of A't'efm "rature'and'pressure to avoidYoverhydrogenationV Y of th alohol.' l'Thecatalyst' is of the sulfur-sensitive type,

to in' re't'he'eiriovalof sulfur, and may includenickel,V

copper, halt metal.- They are used in a" iinelyY divided foi-in to sent a'large contact surface, and by their use substantially sulfur-free alcohol product is obtainable. The'sve'cond 'hydroggenation,` oi' hydrode'sulfurization, is preferably car'r'ied'out at Vrelatively low-pressures of 'atmsphei'i'c to 50'0 p. s. i. g. and temperatures oflOO to `400 F. Itvvas' found that alcohol productswhich, prior' to"the"' hydrodesulfurization treatment, had sulfurvcon- Vtents of'lO t'3'0`parts per million could be reduced to a Yspending"iinprniement in ester color could also Vbe ob- Y Vzat'ioncatalysts,"such as nickel, not only are `sulfur-sensitive," iks/a desirable quality, but vare also carbon 4 Y Y Y Commercial hydrogen `contains significant quantities-ofcarbon monoxide, usually 2 to 3%. Employing such gas inthe hydrodesulfurization reaction with nickel catalyst results, under the reaction conditions, in the formation of nickel carbonyl. This property naturally depletes the catalyst, but more seriously still,-.results `in the contamination of thealcohol product with this material;4 subsequent Ydistil-V lationr of the lreaction product inthe stillY causes fdecomposition :of lthe Ni (CO 4, fouling thelequipmentg an .d1-1deV positing .nickel therein which, :in fthepresence .off thellal cohol product, results in conversionI of signilicantamounts. of thelatte1=tothe aldehyde. and tl.`ehydrocarbonl byV de-V,

Itis one of'the purposes ofthe present mventionto provide an improvd'means forV hydrodesulfurizing the Oxo alcohol product "in .the presence, of a' CO-sensitive catalyst whereby commercial hydrogen, andspeciically carbon -monoxidecontaining hydrogen, may be employed.V It is valso a purpose ofthe present. invention to carryY out 'alcohol hydrodes'ulfurization under conditions Vsuch that overhydrogenation is minimized; Y j Otherobjects and -advantages'of the invention Will appear hereinafter.

In accordance with the present invention; thedifliculties inherent in'the formation of volatile carbonyls by reaction `of Ythe nickel hydrodeslfurization catalyst `.with CO-containing gas streams areove'rcome-by stripping out the carbonyls fromthe alcohol product with hydrogen at essentially'the same temperature, orlower, as that-obtaining in the hydrodesulfurization ozone. The 'gas stream, containing the metal carbonyl, Hz, andA some alcohol vapor are thereafter passed to the thermal treating zone wherein the carbonyl is decomposed to the correspondinginetal, such as nickel, vand carbonmonoxide is liberated. Y Y

i Inone modication ofthe invention, thejdecomposition zone is maintained under conditionsfwherebythe CO4 liberated is Vconverted to Vmethane by the nickel or ,other catalyst 'which lhas beenv deposited in that zone, inV thepresence of ,the large excess of hydrogen present. YThis methanized hydrogenisrecycled tov the hydrode- .sulfurization zone to augment 4theJ CO-contaminated commercial hydrogen'used. in the process.

/ "The gaspurgingoperation isV always accompaniedby Y tion, 4into the corresponding o'len and aldehyde.v These materials are returned to thel corresponding carbonylation and hydrogenation stages.

The amount-'of sulfur inalcohol product beingvei'y Y small, only aV relatively small hydrogen. circulation is required,`andV substantially total gas 'recycle .is desirable, for vthus the catalyst'life isv prolonged,`r by minimizing nickel carbonyl formation.' The system .combining ,ay low temperature hydrodesulfurization section vvitha high temperature carbonyl decomposition section., permits operation WithCO-'c'ontaining gases. atlow.,catalyst` temperatures, which operation Vis ordinarily. not feasible. The high temperature zone vcontains no catalyst'otl'ler than that Yfrom decomposed carbonyls, which reduces the dergree of overhydrogenation inA this section, particularly in view' ofthelrelatively small amount of alcohol product in the vapor phase. Y

"hepresent invention 1and itsA applications willbe'stbe ln the course of the decomposition V'of understood from the more detailed description herein-k after, wherein reference will be had to the accompanying drawing, which is a schematic representation of a system suitable for carrying out preferred embodiments of the invention. As the latter resides in the treatment of the alcohol product from the aldehyde hydrogenation step and inds its highest utility when a sulfactive catalyst is employed in that stage, the carbonylation and decobalting are not shown. y

Referring now to the drawing, liquid aldehyde product Isubstantially free of dissolved cobalt, and which may contain as much as 0.005% sulfur, is passed to the lower portion of hydrogenator 2 via line 4. Simultaneously, commercial hydrogen is supplied to reactor 2 through line 6 in amounts suicient to convert the aldehyde product into the corresponding alcohols. The catalyst within reactor 2 is preferably a sulfactive one; an excellent catalyst is one comprising molybdenum sulide supported on an activated carbon support. Hydrogenator 2 may be operated at pressures of from about Z500-4500 p. s. i. g. and temperatures of from about 400 to 550 F., and a liquid feed rate of about 0.25 to 2 v./v./hr. It is also beneficial to add to the hydrogenation zone up to 1-10% of water, to aid in selectivity to alcohol product.

The products of the hydrogenation reaction are withdrawn overhead through line 10, then passed through cooler 12 into high pressure separator 14, where unreacted hydrogen may be withdrawn overhead through line 16 for further use in the system. Liquid products are withdrawn from separator 14 through line 18 and are passed to still 22 through pressure release valve 20. As

pointed out, the crude alcohol product has a compara-l tively high sulfur content of -30 parts per million. If relatively freshly prepared catalyst is employed, the sulfur content may be even higher. This is true even if the aldehyde feed to the hydrogenation zone 2 had a lower sulfur content. In still 22 the low boilers, mostly hydrocarbons boiling below the desired alcohol product, are distilled overhead. Thus, when a C7 olefin fraction is the feed to the carbonylation zone, generally the product boiling up to about 340 F. is removed as a heads cut in still 22 and used as fuel blending agent.

The bottoms from this primary distillation are withdrawn through line 26 and passed to alcohol still 2S, where product alcohol is removed overhead through line 30 by distillation at atmospheric or reduced pressures. The bottoms from the distillation may be further processed, or used as fuel.

The recovered alcohol product, containing excessive quantities of sulfur in solution, is passed via line 30 into the lower portion of hydrodesulfurization reactor 34. In zone 34, the alcohol product is contacted with a sulfursensitive catalyst, such as nickel, cobalt, platinum, palladium, copper and the like, in the presence of commercial hydrogen introduced through line 36 and recycle hydrogen. The reaction conditions Within 34 include pressures in the range of atmospheric to 3000 p. s. i. g., preferably atmospheric to 500 p. s. i. g., and temperatures in the range of 100 to 400 F., preferably 200 to 300 F. The hydrogen throughput based on alcohol is 10 to 500 C. F./B. This fresh hydrogen admitted through line 36 may contain up to 5% CO.

The liquid and gaseous product from the hydrodesulfurization zone is passed via line 37 to a gas-liquid separation zone 33. The hydrogen gas separated in said zone is preferably completely recycled to reactor 34 via lines 40 and 36. This gas contains some nickel carbonyl, which is extracted and dissolved by further contacting with alcohol product in the hydrodesulfurization zone. Complete recycle decreases the amount of additional make-up, i. e., fresh hydrogen required, andthus minimizes nickel catalyst losses.

The liquid product withdrawn from the separation zone 38 is passed via line 42 to gas stripping zone 44. The liquid product, though ysubstantially completely free of sulfur, contains in solution significant amounts of th.

carbonyl of the hydrodesulfurization catalyst, such as nickel carbonyl. Stripping gas is now introduced into vessel 44 through lines 46 and 48. As a stripping gas there may be employed H2, CO, mixtures of H2 and CO, nitrogen, methane, and the like. Temperatures for stripping depend upon the nature of the carbonyl, and the pressure in the zone. Thus suitable reaction conditions within 44 include temperatures of 50 to 400 F. and

pressures of from l5 to 500 p. s. i. g. If nickel carbonyl is stripped, temperatures from 50-250 F. and pressures from 15-100 p. s. i. g. are suitable.

The stripped alcohol product, now free of dissolved carbonyl as well as sulfur, is withdrawn from stripper 44 through line 50, and is now ready for employment in processes requiring a high purity alcohol. Gaseous products containing a minor amount of vaporized and entrained alcohol is Withdrawn overhead through line ,b2A

and may be passed, if desired, to another gas-liquidseparator 54. A portion of the gas removed in thi-s separation zone may be recycled to stripper 44 via line 48.

However, it may be desirable to bypass separator 54 and pass the total gas and vapor stream through lines 56 and 58 into thermal treating zone 60.

Zone 60 is maintained at a temperature level of 400 to 800 F., preferably 500 to 700 F. In the thermal zone, nickel carbonyl is completely decomposed into carbon monoxide and the metal, which deposits in theA reactor. Heating may be by any suitable means, as electrical means, steam coils, and the like. The small amount of alcohol product carried into zone 60 is converted as a result of interaction with the deposited nickel,

into aldehyde and olefin. The amount of alcohol thus, carried over is usually Very small, not more than abouti 1% of the amount treated by the hydrodesullurizingY technique. Olen and aldehydes thus produced may addrogen, passage through the thermal zone results in some hydrogenation of the carbon monoxide, resulting in at least partial methanization. This gas, after removal of liquid products, may be passed to the hydrodesulfurization stage via lines 62 and 36 and provides a gas with minimum catalyst poisoning components.

The proces-s of the present invention may be subject to many modications obvious to those skilled in the art. Thus, under certain circumstances it may be desirable to maintain a sulfur sensitive and CO sensitive hydrogenation catalyst both in the aldehyde hydrogenation and in the hydrodesulfurization zones. Also, under certain circumstances, it may be desirable to pass the entire crude alcohol product prior to distillation directly into the hydrodesulfurization zone, and distill only the alcohol hydrodesulfurized and stripped according to' the f present invention.

In still another modification of the present invention steam or water vapor is introduced along with the feed to thermal reactor 60 through line 70. The steam vthus admitted, which may in amount be varied widely from` l to 10% of the material passed to zone 60, -serves the 'f dual function of minimizing dehydration-dehydrogena-v tion of the entrained alcohol vapors, and also serves to remove carbon monoxide by the Water gas shift reaction CO-l-HzOCOz-i-Hz, which reaction is favoredl under the temperatures obtaining in zone 60. When steam is thus admitted, the eiiiuent from the thermal unit 60 may be passed through a condenser, the gas separated and passed to the hydrodesulfurization or stripping zone,fthe alcohol product separated from water, and the'alcohol product combinedswitlrtthe; mairLaleohoLproduct withi-V "Ihecinvention' maybe 'furtherillustratedzbyitheflfolf;

lowingcspecic examples. Y

jim: Y EXAMPLEir; Y Studies lon; acon tinu'ousoperation in Whiche'isoctyl'` alcoli s-rrepare'd by .the f catalytic hydrogenationfof an, oaanauon Aprochictiusirig a. suldewcatalyst- .insthe initialY 'hydrogenationg and a sulfur-sensitive; catalystV in, the-v Table 1V c 'ONTiNUoUs OPERATION WITnsnLFIDE CATALYST 1N F1 AND'SULEURSENSITIVE yCALLYSTINSECOND STAGE Thisseperimentpointszout thatztherhydrogenf.usedtime Y hydrodesuliulizingz alcoholsrfdoesfnot :require removal. o: carbono monoxide; butzfrathergthat i. nickel carbonyl* per; VSefis an etectiveaie or:prepared'rinsituf` )whatiszclailuedrlsVK v 1g Armv improved; process- 'for hydrodesulfnrfizing i' as,

sulfur-.contami nated alcoholl product prepared; by. the;y j 5 carbonylation of olens in the presenceoiraI cobaltcatalysty tosfvorm; aufaldeh-ydefproductwhich thereafter is hydrogenated to form ysaid 'sulfur-contaminated alcoh'ol.'l

'product twhich comprisesl passing. said impure alcohol'zproductgto a;hydrodesulfurizationvzone; maintainingfin'g,

said zone; vaacatalyst-which; :forms metal vcarbonyls ini thea presence of carb'onqmonoxide; passinginto said zone gai;

carbon: monoxide comprisingfhydrogenfgas.` maintaning.

RST STAGE '1 Fmi A "YB j Feeda o D.

Avg:Tmp'F 290' V290 290 300 L1qmd,v./v./hr -V 1,0Y 4.0 1.0 4.0. Light Ends, Wt. per Y 't 0.40 0.33 0.58 0:51` s 1-3v 4 5 0-3 1. 0.15 0. 03-0. 05 0. 0s 0. 00-0. 13 00a-0.04 0,04-.0c0su VEXAMPLl-wll.y agpressureof :abouti-atmospheric.1053000 'p.- s, i. g., and:

Asv .further evidence of colorA improvement resulting fr om hydrodesulfurization, w recycle' esterication tests Va@temperaturerof-.110052 to AOOWF.; in said zone, convert.V

Were carried'out on alcohol Which'had beensubjected to .a

ajhydrodesulfurization treatment'at 300 Fiandl v./v./

hr. Vat ai'catalyst age of 600 hours.y The tests involved recycle of thestainless steel lingsrursed in the esterication-test"a'nd therefore represent rsevereV conditionsjsuch aswould be encountered in plantesterification operations.- The excellentproperties of the hydrodesulfurized alcohol' are. illustrated in Table Il shown below, in which theV Y light AabsorbencyV of the total phthalate esters preparedV from the Avarious recycled alcohols are summarized.

Trble II LIGHT a-BsoRBENCY M4470 A'. 0F TOTAL PHTHALATE l Y EsTERs.- Y Y Ester Product of Untreated Alcohol Erster Productof'Hydrodesulfurlzed Alcohol Cycle UHKNNH CODO 4'l'v'headvantage of.' hydrodesulfur-izing a sulfur-contaminatedfalcohol product; with 4a CO-containing hydro* gen-gasover treating the same lwitha CO-free gas, in Vtl:l e i,presenc e. of -a CO and sulfur V.sensitive catalyst is brought out inthe following example.

Y EXAMPLE Y III foi-plasticizing purposes,.whereas the alcohol prior to this'ftreatment was not suitablefor lmaking esters to be usedasclorless'plastiizers.'

The* alcohol product Vthus treated. had an ester color of 0.08, whichmade itsuitable hydrodesulfurization zone.

' separating; said ;liq'lid.I substantially :free Y.of sulfur and:i

containingrin-1 solution metal carbonyl Vfrom'said etluenb gasesgrecyclingat'least a'portionaof said; gases to'saidl# hydriodesulfurization' zone. vpassing Asaid liquidand dis` solved'Ymetal-carbonyl'to a stripping zone, maintainingxa` temperature of fromaboutfSO". to A400" Fsiandra pressure-5y of.from;aboutjatmosphericto*about 500p. s. i.` g.k insaidV zone, .strippingmetal carbonylvfromthe alcoholiliquidin said? zone, recovering; anil alcohol productE substantially completely free1of-sulfurand dissolved metal carbonyl' from1w$adgznerf withdrawing strippingg'gas andrmetal carbonyl from said zone, passing said stripping-'gas toa.- lthermal:treating zone ,ata temperature of-fromabout 4009? to about-SOOP-IFT, heating fsaidgas stream in saidzone Vtodecon:xp osesaid -metalr carbonyl,L and recovering;

a" arbonunonoxide containing gasV from said last lnamed 1 zone. Y Y Y `2.1'I'heprocess of claim 1 wherein the carbon monox?l ide produced on. decomposing said metalv carbonyl iis' hydrogenated. in 'the presenc'egof the metal 1 "esultingfrom, V said decomposition to producen methane-,comprising gas.` i 3.-.The process. ofclair'n 2- fwherein said methane-comprisingcgas is passed-tosaidl desulfurizaticn zone.V

: 4. The process of-claim 1 .wherein said hydrodesulfuris j zation catalyst comprises nickeland said'metal carbonyl is nickel carbonyl.- Y

- 5;;"I'hef5processof.claimf1'wherein steam is added tot f said thermal'zone and'sad'carbonmonoxide is convertedV at leastfin part to carbondioxide. Y

6.1The Y process of claim 1 wherein carbonyls arestripped'out of said carbonyll containing alcohol product ata temperature-n0 higher-Vthan'jthat prevailing in .said

7:' An" improved process f for sulfur contaminated alcohol with arminor amountofn nickelrcarhonyl. and thereafter passing a stripping gas` to@` Y' suliurizingzagenn'when added as suc'ln Y Y v hydrodesulfurizingV al Y sulfur contaminated lalcohol whichY comprises treating rva 9 said treated alcohol product, stripping out said nickel 2,569,671 carbonyl and recovering a high quality alcohol product. 2,585,816 2,638,488 References Cited in the le of this patent 2,700,687

UNITED STATES PATENTS 5 2,464,916 Adams et a1. Mar. 22, 1949 2,525,354 Hoog et al. Oct. 10, 1950 2,557,701 Smith .Tune 19, 1951 10 Hughes et a1. Oct. 2, 1951 Mertzweiller Feb. 12, 1952 Cerveny May 12, 1953 Catterall Jan. 25, 1955 OTHER REFERENCES Groggins: Unit Processes in Org. Chem. (4th ed.), McGraw-Hill, N. Y. (1952), PP. 561-4. 

1. AN IMPROVED PROCESS FOR HYDRODESULFURIZING A SULFUR-CONTAMINATED ALCOHOL PRODUCT PREPARED BY THE CARBONYLATION OF OLEFINS IN THE PRESENCE OF A COBALT CATALYST FO FORM AN ALDEHYDE PRODUCT WHICH THEREAFTER IS HYDROGENERATED TO FORM SAID SULFUR-CONTAMINATED ALCOHOL PRODUCT WHICH COMPRISES PASSING SAID IMPURE ALCOHOL PRODUCT TO A HYDRODESULFURIZATION ZONE, MAINTAINING IN SAID ZONE A CATALYST WHICH FORMS METAL CARBONYLS IN THE PRESENCE OF CARBON MONOXIDE, PASSING INTO SAID ZONE A CARBON MONOXIDE COMPRISING HYDROGEN GAS, MAINTAINING A PRESSURE OF ABOUT ATMOSPHERIC TO 3000 P. S. I. G., AND A TEMPERATURE OF 100* TO 400* F., IN SAID ZONE, CONVERTING AT LEAST A PORTION OF SAID CATALYST IN SAID HYDRODESULFURIZATION ZONE TO THE METAL CARBONYL, WITHDRAWING A MIXTURE COMPRISING EFFLUENT GASSES AND A LIQUID PRODUCT SUBSTANTIALLY FREE OF SULFUR COMPOUNDS FROM SAID ZONE, PASSING SAID MIXTURE TO A GAS LIQUID SEPARATION ZONE, SEPARATING SAID LIQUID SUBSTANTIALLY FREE OF SULFUR AND CONTAINING IN SOLUTION METAL CARBONYL FROM SAID EFFLUENT GASES, RECYCLING AT LEAST A PORTION OF SAID GASES TO SAID HYDRODESULFURIZATION ZONE, PASSING SAID LIQUID AND DISSOLVED METAL CARBONYL TO A STRIPPING ZONE, MAINTAINING A TEMPERATURE OF FROM ABOUT 50* TO 400* F. AND A PRESSURE OF FROM ABOUT ATMOSPHERIC TO ABOUT 500 P. S. I. G. IN SAID ZONE, STRIPPING METAL CARBONYL FROM THE ALCOHOL LIQUID IN SAID ZONE, RECOVERING AN ALCOHOL PROUCT SUBSTANTIALLY COMPLETELY FREE OF SULFUR AND DISSOLVED METAL CARBONYL FROM SAID ZONE, WITHDRAWING STRIPPING GAS AND METAL CARBONYL FROM SAID ZONE PASSING SAID STRIPPING GAS TO A THERMAL TREATING ZONE AT A TEMPERATURE OF FROM ABOUT 400* TO ABOUT 800* F., HEATING SAID GAS STREAM IN PAID ZONE TO DECOMPOSE SAID METAL CARBONYL, AND RECOVERING A CARBON MONOXIDE CONTAINING GAS FROM SAID LAST NAMED ZONE. 